G. Vaughan (U. Manchester) – SAOZ system for NO2 and ozone operated since 1991. Also operated at Lerwick, UK (60.1˚N, 1.1˚E) and Aberdeen, UK (57˚N, 2˚W) during the EASOE (November 1991 to April 1992) and SESAME (February to April 1994) campaigns, respectively.